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Restructuring and impairment (credits) charges - Charges Recognized (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 27, 2020	Sep. 29, 2019	Sep. 27, 2020	Sep. 29, 2019
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ (3,659)	$ 1,268	$ 16,692	$ 13,437
Asset impairment charges				6,911
Restructuring and impairment charges	(3,659)	1,268	16,692	20,348
Termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges	(4,413)	906	15,224	11,772
Asset impairment charges				0
Restructuring and impairment charges				11,772
Other Restructuring costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	754	362	1,468	1,665
Asset impairment charges				6,911
Restructuring and impairment charges				8,576
2020 Workforce reduction plan
Restructuring Cost and Reserve [Line Items]
Restructuring charges	(216)		10,348
2020 Workforce reduction plan \| Termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges	(471)		10,093
2020 Workforce reduction plan \| Other Restructuring costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	255		255
2019 Footprint realignment plan
Restructuring Cost and Reserve [Line Items]
Restructuring charges	(417)	622	826	13,168
2019 Footprint realignment plan \| Termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges	(785)	584	367	13,100
2019 Footprint realignment plan \| Other Restructuring costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	368	38	459	68
2018 Footprint realignment plan
Restructuring Cost and Reserve [Line Items]
Restructuring charges	(2,923)	389	5,069	(741)
2018 Footprint realignment plan \| Termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges	(3,006)	315	4,853	(1,523)
2018 Footprint realignment plan \| Other Restructuring costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	83	74	216	782
Other restructuring programs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	(103)	257	449	1,010
Other restructuring programs \| Termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges	(151)	7	(89)	195
Other restructuring programs \| Other Restructuring costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 48	$ 250	$ 538	$ 815